This invention relates to an apparatus for detecting photographic image information of an original photographic film such as a film negative in a photographic printer by entirely dividing image information into a plurality of aligned picture elements to be detected.
With a photographic printer, it is generally required to measure a density of an original film, for example a film negative, for detecting the printing exposure amount or correction amount, and in the prior art of this field, the large area transmittance density (LATD) of the film negative is measured by photo-sensitive sensors such as photodiodes disposed near a light passage of a printing lens unit. However, in the image detection method by means of this LATD, the average density of the image of the film negative is measured and detected by the photo-sensitive sensors and the image density is not accurately detected entirely throughout the image surface, so that the printing exposure or correction cannot be correctly performed. In the prior art, there has also been proposed a method in which the image surface of the film negative is divided into a plurality of equally aligned picture segments, and the light passing the segments is measured, and the densities detected in accordance with the measured light are corrected after the printing exposure amount was determined. However, with this method, since the light measurement of the film negative is only carried out approximately, it is difficult to accurately detect information regarding detail of the image of the film negative.